1. Technical Field
The present invention relates to a tape carrier, a semiconductor device, and a method for manufacturing semiconductor device.
2. Related Art
Size and weight reduction of electric products such as liquid crystal panels and mobile terminals is advancing. These electric products include integrated circuit devices, and these devices packaged inside cases are generally mounted on insulating film substrates that can be bended easily, for instance, by hand. These film substrates are formed with, for instance, polyimide, and are called tape carriers or flexible substrates. Packaged products including integrated circuit devices mounted on such tape carriers are called tape carrier packages (TCP), chip on films (COF), or flexible print circuits (FPC). Refer to JP-A-2004-235322 and JP-A-2000-269249 for examples.
FIGS. 4A and 4B are plan views showing an example of a structure of a tape carrier 200 according to an example of a related art. FIG. 4A illustrates a status before stamping the long tape carrier 200 along cut lines 251 which are the outlines of the final product regions. The tape carrier 200 includes an insulating base film 201, inner and outer leads (hereafter referred to as “leads”) 203 provided thereon, and solder resists 205 which mainly cover the inner leads.
Each of the solder resists 205 covering the leads 203 is formed with resin by coating a base film 201 in a state before forming the leads 203, using dispensing or screen printing, and thereafter curing it (i.e. carrying out heat treatment). Here, since the solder resist 205 before being cured is in a liquid state with a certain degree of viscosity, the edge of the fluid rises by the effect of the surface tension during the steps of coating to curing. In other words, as shown in FIG. 4B, a part in each of the solder resists 205, positioned inward from the edge thereof by approximately 0.5 to 0.8 mm, is thicker compared to the center part, resulting in a problem of unevenness in film thickness. Since the solder resists 205 are translucent, the uneven film thickness tends to cause color irregularities, i.e., defect in the outer appearance.
Moreover, as shown in FIG. 5, subsequent to packaging an integrated circuit (IC) device 211 and stamping the tape carrier 200 along the cut lines 251, the tape carrier 200 is bended at a bending line 261. At this time, a thick film portion 205a in each of the solder resists 205 behaves like a core, preventing a smooth bending. In particular, if the thicknesses of the thick solder resist portions 205a are uneven, the tape carrier tends to bend at a portion in the thick solder resist portions 205a which are thinner and weaker. This results in the irregularities of bending, i.e., defect in bending.